Yahoo chief operating officer Henrique de Castro, the recruit Chief Executive Officer Marissa Mayer poached from Google shortly after she took the company's lead, will leave on Thursday.

Yahoo did not give a reason for his departure, but the Recode technology blog reported that Mayer had fired him.

Marissa Mayer had hired de Castro in order to bring his Internet advertising expertise into the company. However, Yahoo's revenue has declined in recent years amid competition from Google and Facebook.